Antarctic krill (Euphausia superba)(hereafter krill), are one of the most important components of the Antarctic ecosystem food web. Area 48 of the Commission on the Conservation of Antarctic Marine Living Resources (CCAMLR) is in the Atlantic sector of the Southern Ocean, and is the primary fishing ground for commercial krill fishing fleets. We evaluated the changes in catch rate over time in this region using average catch rate data derived from a database which covers CCAMLR subareas 48.1 (50°W−70°W, 60°S−65°S), 48.2 (30°W−50°W, 57°S−64°S), and 48.3 (30°W−50°W, 50°S−57°S) from 1982 to 2011 using the Mann–Kendall(M–K) method. The average nominal CPUE was ~5 t/h in 1982 and increased to 10 t/h by 2011 in Area 48. The standard deviation for these estimates was very large and almost equal to the mean. Nominal CPUE fluctuated periodically, but the linear trend growth per year was 0.221 t/h. Subarea 48.1, the primary fishing area, had a linear trend growth per year of 0.088 t/h. Subarea 48.2 accounted for the biggest proportion of the increase in Area 48, increasing at a rate of 0.323 9 t/h per year. The rate of increase in subarea 48.3 was 0.261 t/h per year. In the past 30 years, the krill catch rate in area 48 increased slowly at first, then rapidly up to 1999, before undergoing a significant change after 2001. After the late 1980s, and concomitant with a decrease in the southwest Atlantic sector krill resource, catch rates followed an upward trend as fishing technology improved. The mutation point in area 48 in 1999 occurred at the same time as the Japanese fleet catch rate increased significantly, accounting for more than 70% of the global catch. The mutation points of catch rate occurred in 2001 and in 2004 in subarea 48.1, though they were not significant. There was retraction of sea ice area from 2001 to 2003 resulting in a rebound in krill populations and a subsequent increase in catch per unit effort (CPUE) in 2004. There were two mutation points of catch rate in subarea 48.2, the first one occurred in 1995–1996, and was a downward change point that did not pass the α=0.05 significance level. The second event occurred in 1996–1997 and passed the α=0.05 significance level in 2000. The mean density of post-larval krill during 1976–2003 in the southwest Atlantic sea was lowest in 1994, resulting in lower harvest during 1995–1996. Recruitment restored normal and the catch rate mutation points in subarea 48.2 appeared in 1996–1997. The mutation points of catch rate occurred in 1992 in subarea 48.3, and passed the α=0.05 significance level in 1996. After the breakup of the former Soviet Union in 1991, the size of the Russian and Ukrainian trawler fleet declined sharply because fuel subsidies were canceled. The catch by the former Soviet Union before 1992 was about 84% of the world total, but after 1992 the global catch was made predominantly by vessels from Japan, which has a CPUE more than twice that of the former Soviet Union’s fleets. At a spatial level, the fishing effect dominates the three subareas, but the impact of sea ice coverage is more significant when closer to the shelf of the Antarctic Peninsula.